1. Field of the Invention
This invention relates to a color diffusion transfer photographic material, and especially to a color diffusion transfer photographic image-receiving material.
2. Description of the Prior Art
Various methods of color diffusion transfer photography are known and include, for example, the method involving the use of a dye developer as disclosed in U.S. Pat. No. 2,983,606, the method involving the use of a diffusible dye formed by the reaction of a color former and an oxidation product of a developer as disclosed in U.S. Pat. Nos. 3,227,550 and 3,227,551, or the methods disclosed, for example, in U.S. Pat. No. 3,628,952 or Japanese Patent Publication No. 10240/59. These prior methods have aspects in common in that a combination of an image-receiving layer and a silver halide emulsion layer containing a dye image forming substance is used, and the silver halide emulsion layer after exposure is treated with an alkaline processing solution of high pH thereby to transfer the diffusible dye to the image-receiving layer.
It is well known on the other hand that a synthetic polymer is used as a film-forming material in a color diffusion transfer image-receiving material (see, for example, U.S. Pat. No. 3,148,061). However, since the synthetic polymer should have the function of receiving the dye upon being processed with the alkaline processing solution, it is difficult to render the synthetic polymer alkali resistant and especially water resistant.
As is well known in the art, the general procedure for rendering the photographic layer processing resistant, such as alkali resistant and water resistant, is to incorporate a cross-linking agent in the photographic layer. In fact, a cross-linking agent such as formaldehyde or glyoxal is used in color diffusion transfer photographic materials.
Since gelatin is generally used as a film-forming substance (binder) in photographic materials, the use of such a cross-linking agent as mentioned above is sufficient. However, synthetic polymers, especially polyvinyl alcohol, can not be fully cross-linked with these cross-linking agents. This deficiency is especially marked when the polymers are processed at a high pH.